Publications by authors named "Thole H"

Article Synopsis
  • Oral drug absorption, particularly of clofazimine, can be significantly affected by diarrhea associated with infections like cryptosporidiosis in HIV-infected adults.
  • A population pharmacokinetic model using data from a study of 23 participants revealed that severe diarrhea can reduce clofazimine bioavailability by more than sixfold.
  • Understanding these effects is crucial for optimizing dosing regimens to improve treatment outcomes for patients experiencing gastrointestinal issues.
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The COVID-19 pandemic has profoundly impacted health systems globally and robust surveillance has been critical for pandemic control, however not all countries can currently sustain community pathogen surveillance programs. Wastewater surveillance has proven valuable in high-income settings, but less is known about the utility of water surveillance of pathogens in low-income countries. Here we show how wastewater surveillance of SAR-CoV-2 can be used to identify temporal changes and help determine circulating variants quickly.

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Article Synopsis
  • Cryptosporidium is a gut pathogen that particularly affects people with weakened immune systems, such as those with HIV, and the CRYPTOFAZ trial in Malawi tested clofazimine's effectiveness for treating this infection.
  • The study used various diagnostic methods, including qPCR and ELISA, to examine 586 individuals and monitor those who were part of the trial for pathogen shedding and other co-infections.
  • The findings revealed that while qPCR was more sensitive for detecting Cryptosporidium, ELISA had more variable results; additionally, a new Cryptosporidium species was found, and enterotoxigenic E. coli was also linked to diarrhea in some participants.
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The COVID-19 pandemic continues to impact health systems globally and robust surveillance is critical for pandemic control, however not all countries can sustain community surveillance programs. Wastewater surveillance has proven valuable in high-income settings, but little is known about how river and informal sewage in low-income countries can be used for environmental surveillance of SARS-CoV-2. In Malawi, a country with limited community-based COVID-19 testing capacity, we explored the utility of rivers and wastewater for SARS-CoV-2 surveillance.

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The SARS-CoV-2 Omicron variant has resulted in a high number of cases, but a relatively low incidence of severe disease and deaths, compared to the pre-Omicron variants. Therefore, we assessed the differences in symptom prevalence between Omicron and pre-Omicron infections in a sub-Saharan African population. We collected data from outpatients presenting at two primary healthcare facilities in Blantyre, Malawi, from November 2020 to March 2022.

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Background: Compared to the abundance of clinical and genomic information available on patients hospitalised with COVID-19 disease from high-income countries, there is a paucity of data from low-income countries. Our aim was to explore the relationship between viral lineage and patient outcome.

Methods: We enrolled a prospective observational cohort of adult patients hospitalised with PCR-confirmed COVID-19 disease between July 2020 and March 2022 from Blantyre, Malawi, covering four waves of SARS-CoV-2 infections.

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Article Synopsis
  • The study investigates COVID-19 patient outcomes and viral lineages in Malawi, highlighting a lack of data from low-income countries.
  • Conducted from July 2020 to March 2022, researchers analyzed 314 hospitalized patients, discovering distinct variants during each wave—B.1, Beta, Delta, and Omicron.
  • Results indicated that patients during the Delta wave had higher mortality rates compared to earlier waves, while those infected with Omicron showed fewer chronic conditions and required less intensive treatment.
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Background: Collecting sputum specimens is a challenge in infants and young children. We assessed the performance and safety of induced sputum (IS) collection in this population, embedded in a prospective study evaluating respiratory cryptosporidiosis in Malawian children with diarrheal disease.

Methods: We assessed the sputum quality and correlation with detection of Cryptosporidium spp.

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Background: Respiratory cryptosporidiosis has been documented in children with diarrhea. We sought to describe the dynamics of respiratory involvement in children hospitalized with gastrointestinal (GI) diarrheal disease.

Methods: We conducted a prospective, observational longitudinal study of Malawian children 2-24 months hospitalized with diarrhea.

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P-glycoprotein (Pgp) detoxifies cells by exporting hundreds of chemically dissimilar hydrophobic and amphipathic compounds and is implicated in multidrug resistance (MDR) in the treatment of cancers. Photoaffinity labeling of plasma membrane vesicles of MDR CHO B30 cells with the anthracycline [ I]-iodomycin, subsequent sequential cleavage with BNPS-skatol and endoproteinase Lys-C, and the Edman sequencing of the purified photoaffinity-labeled peptide identified the lysine residue at position 268 in the hamster Pgp primary sequence as the major photobinding site of iodomycin in CHO B30 cells. Lysine 268 is located adjacent to the cytosolic terminus of transmembrane 5.

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Background: An effective drug to treat cryptosporidial diarrhea in HIV-infected individuals is a global health priority. Promising drugs need to be evaluated in endemic areas which may be challenged by both lack of resources and experience to conduct International Committee of Harmonisation-Good Clinical Practice (ICH-GCP)-compliant clinical trials.

Methods: We present the challenges and lessons learned in implementing a phase 2A, randomized, double-blind, placebo-controlled trial of clofazimine, in treatment of cryptosporidiosis among HIV-infected adults at a single site in Malawi.

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Patient registries offer a powerful and practical means of real-world data collection system for rare diseases. Many guidelines have been released to standardize patient registries, although most of them do not address issues specific to rare disease patient registries. In November 2018, the European Medicines Agency (EMA) released a draft discussion paper on methodological and operational aspects of disease registries and made proposals on good registry practice (henceforth referred to as EMA guidance).

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Background: We evaluated the efficacy, pharmacokinetics (PK), and safety of clofazimine (CFZ) in patients living with human immunodeficiency virus (HIV) with cryptosporidiosis.

Methods: We performed a randomized, double-blind, placebo-controlled study. Primary outcomes in part A were reduction in Cryptosporidium shedding, safety, and PK.

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An expanding body of evidence indicates the possible role of estrane derivatives as useful anticancer agents. The aim of this study was to describe the cytotoxic effects of 63 newly synthetized estrone-16-oxime ethers on human cancer cell lines (cervix carcinoma HeLa, breast carcinoma MCF7 and skin epidermoid carcinoma A431), studied by means of the MTT assay. Four of the most promising compounds were selected for participation in additional experiments in order to characterize the mechanism of action, including cell cycle analysis, morphological study and the 5-bromo-2'-deoxyuridine incorporation assay.

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Background: While methods for the production of guidelines (evidence analysis, assessment, adaptation) have been continually refined throughout the past years, there is a lack of instruments for the production of easily understandable synopses.

Methods: Definition of a methodological approach to encompass synopses by Spidernet diagrams.

Results: Tables of synopses can be generated with distinct information to bring down the main results in one Spidernet diagram.

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In the search for novel biomarkers of endometriosis, we selected 152 genes from the GeneLogic database based on results of genome-wide expression analysis of ovarian endometriosis, plus 20 genes related to estrogen metabolism and action. We then performed low-density array analysis of these 172 genes on 11 ovarian endometriosis samples and 9 control endometrium samples. Principal component analysis of the gene expression levels showed clear separation between the endometriosis and control groups.

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Steroid-related cancers can be treated by inhibitors of steroid metabolism. In searching for new inhibitors of human 17beta-hydroxysteroid dehydrogenase type 1 (17beta-HSD 1) for the treatment of breast cancer or endometriosis, novel substances based on 15-substituted estrone were validated. We checked the specificity for different 17beta-HSD types and species.

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The enzyme 17beta-hydroxysteroid dehydrogenase type 1 (17beta-HSD1) has become an important drug target for breast cancer because it catalyzes the interconversion of estrone to the biologically more potent estradiol which also plays a crucial role in the etiology of breast cancer. Patients with an increased expression of the 17beta-HSD1 gene have a significantly worse outcome than patients without. Inhibitors for 17beta-HSD1 are therefore included in therapy development.

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Hydroxysteroid (17beta) dehydrogenase 1 (HSD17B1) catalyzes the reaction between the low active 17-ketosteroids and the highly active 17beta-hydroxysteroids. In the present study, we have generated transgenic (TG) mice expressing human (h) HSD17B1 under mouse mammary tumor virus (MMTV) promoter (MMTV-hHSD17B1TG mice). The MMTV-hHSD17B1TG mice were used to characterize HSD17B1 enzyme activity and properties of HSD17B1 inhibitor in vivo.

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Lowering local estradiol concentration by inhibition of the estradiol-synthesizing enzyme 17beta-hydroxysteroid dehydrogenase type 1 (17beta-HSD1) has been proposed as a promising new therapeutic option to treat estrogen-dependent diseases like endometriosis and breast cancer. Based on a molecular modelling approach we designed and synthesized novel C15-substituted estrone derivatives. Subsequent biological evaluation revealed that potent inhibitors of human 17beta-HSD1 can be identified in this compound class.

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17beta-Hydroxysteroid dehydrogenase type 1 (17beta-HSD1) catalyzes the transformation of estrone (E1) into the most potent estrogen, estradiol (E2), which stimulates cell proliferation and decreases apoptosis. 17beta-HSD1 is often strongly overexpressed in estrogen-dependent diseases (like breast cancer and endometriosis). Thus, this over expressed enzyme is a promising novel target for the development of selective inhibitors, which could be used as drugs for the treatment of these diseases.

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Endometriosis is a very common disease in pre-menopausal women, where defective metabolism of steroid hormones plays an important role in its development and promotion. In the present study, we have examined the expression of 11 estrogen and progesterone metabolizing enzymes and their corresponding receptors in samples of ovarian endometriomas and control endometrium. Expression analysis revealed significant up-regulation of enzymes involved in estradiol formation (aromatase, sulfatase and all reductive 17beta-hydroxysteroid dehydrogenases) and in progesterone inactivation (AKR1C1 and AKR1C3).

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17beta-Estradiol (E2) is implicated in the genesis and the development of estrogen-dependent diseases. Its concentration is mainly regulated by 17beta-hydroxysteroid dehydrogenase type 1 (17beta-HSD1), which catalyzes the reduction of the weak estrogen estrone (E1) to the highly potent E2. This enzyme is thus an important target for the treatment of hormone-dependent diseases.

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Human 17beta-hydroxysteroid dehydrogenase type 1 (17beta-HSD1) catalyzes the reduction of the weak estrogen estrone (E1) to the highly potent estradiol (E2). This reaction takes place in the target cell where the estrogenic effect is exerted via the estrogen receptor (ER). Estrogens, especially E2, are known to stimulate the proliferation of hormone-dependent diseases.

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Background: Estradiol (E(2)) is an important promoter of the growth of both eutopic and ectopic endometrium. The findings with regard to the expression and activity of steroidogenic enzymes in endometrium of controls, in endometrium of endometriosis patients and in endometriotic lesions are not consistent.

Methods: In this study, we have looked at the mRNA expression and protein levels of a range of steroidogenic enzymes [aromatase, 17beta-hydroxysteroid dehydrogenases (17beta-HSD) type 1, 2 and 4, estrogen sulfotransferase (EST) and steroid sulfatase (STS)] in eutopic and ectopic endometrium of patients (n = 14) with deep-infiltrative endometriosis as well as in disease-free endometrium (n = 48) using real-time PCR and immunocytochemistry.

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